• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2171-2177
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• 2011

Synthetic route has been developed for the synthesis of new (Z)-5-[4-(2-chloroquinolin-3-yl) methoxy]benzyl-idinethiazolidine-2,4-diones (6a-h) starting from 2-chloro-3-hydroxymethyl quinolines (2a-h). The hydroxy methyl quinolines on tosylation yielded (3a-h). Condensation of the tosyl intermediates with 4-hydroxy benzaldehydes has been carried in DMF in presence of $K_2CO_3$ and obtained 4-quinolinyl methoxy benzaldehydes (4a-h). Conveniently Knoevenagel condensation of quinolinyl methoxy benzaldehydes (4a-h) and 2, 4-thiazolidinedione (5) has been carried in PEG-400 in presence of L-proline and obtained better yields of the titled compounds (6a-h).

• Journal of the Korean Chemical Society
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• v.56 no.3
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• pp.341-347
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• 2012

A series of 2-(4-chlorophenylimino)-5-((3-(p-substituted phenyl)-1-phenyl-1H-pyrazol-4-yl) methylene) thiazolidin-4-one ($\mathbf{3a-h}$) compounds were prepared from the 2-(4-chlorophenylimino) thiazolidin-4-one ($\mathbf{1}$) and 1-phenyl-3-(p-substituted phenyl)-1H-pyrazole-4-carbaldehyde ($\mathbf{2a-h}$). All compounds were characterized by elemental (C, H, N) analysis and spectral (FT-IR, $^1H$ NMR and GC-MS) analysis. These newly synthesized compounds were screened for their antibacterial and antifungal activities. Antimicrobial activity was observed and evaluated against the bacterial strains like Eschericha coli (MTCC 443), Pseudomonas aeruginosa (MTCC 1688), Staphylococcus aureus (MTCC 96), Streptococcus pyogenes (MTCC 442) and against the fungal strains like Candida albicans (MTCC 227), Aspergillus niger (MTCC 282) and Aspergillus clavatus (MTCC 1323). All the synthesized compounds were found to possess moderate to excellent antimicrobial activity against above selected strains.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2367-2374
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• 2013

Lysine (Lys) immobilized on zeolite 4A was prepared by a simple adsorption method. The physical and chemical properties of Lys/zeolite 4A were investigated by X-ray diffraction (XRD), FT-IR, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis. The obtained organic-inorganic composite was effectively employed as a heterogeneous basic catalyst for synthesis of ${\alpha},{\beta}$-unsaturated carbonyl compounds. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present catalyst.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.177-182
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• 2011

A diketo-type ligand was synthesized by the Knoevenagel condensation reaction of thiophene-2-aldehyde with acetylacetone, subsequently its transition metal complexes with Cu(II), Ni(II), and Co(II) chlorides were also prepared. All the complexes were characterized by various physico-chemical methods. The molar conductivity data reveals ionic nature for the complexes. The electronic spectrum and the EPR values suggest square planar geometry for the Cu(II) ion. Interaction of the Cu(II) complex with CTDNA (calf thymus DNA) was studied by absorption spectral method and cyclic voltammetry. The $k_{obs}$ values versus [DNA] gave a linear plot suggesting psuedo-first order reaction kinetics. The cyclic voltammogram of the Cu(II) complex reveals a quasi-reversible wave attributed to Cu(II)/Cu(I) redox couple for one electron transfer with $E_{1/2}$ values -0.240 V and -0.194 V. respectively. On addition of CTDNA, there is a shift in the $E_{1/2}$ values 168 mV and 18 mV respectively and decrease in Ep values. The shift in $E_{1/2}$ values in the presence of CTDNA suggests strong binding of Cu(II) complex to the CTDNA.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2546-2552
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• 2012

A novel biguanide-functionalized $Fe_3O_4/SiO_2$ magnetite nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperbase in chemical transformations. The structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (TEM), powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), elemental analyzer (EA), thermogravimetric analysis (TGA), $N_2$ adsorption-desorption (BET and BJH) and FT-IR. The biguanide-functionalized $Fe_3O_4/SiO_2$ nanoparticles showed a superpara-magnetic property with a saturation magnetization value of 46.7 emu/g, indicating great potential for application in magnetically separation technologies. In application point of view, the prepared catalyst was found to act as an efficient recoverable nanocatalyst in nitroaldol and domino Knoevenagel condensation/Michael addition/cyclization reactions in aqueous media under mild condition. Additionally, the catalyst was reused six times without significant degradation in catalytic activity and performance.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.863-867
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• 2013

A series of azo disperse dyes having dicyanovinyl groups was synthesized by the Knoevenagel condensation with malononitrile from carbonyl substituted phenylazo disperse dyes which were prepared by conventional diazo coupling reaction of aniline derivatives as diazo components. A variety of coupling components such as anilines, an indole and a pyridone were used. The azo disperse dyes were evaluated for their spectral properties and dyeing assessment on the polyester fabrics. The azo disperse dyes containing dicyanovinyl groups showed bathochromic shifts and darker colors due to increased electron withdrawing strength in their azo components and extended conjugation by dicyanovinyl groups than their parent carbonyl substituted azo dyes. The dyes containing 2-acetylamino-5-methoxy substituent in the coupling component exhibited higher wavelength of maximum absorbance (${\lambda}_{max}$) and significant negative solvatochromism than those of other dyes due to intramolecular hydrogen bonding.

• Journal of the Korean Chemical Society
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• v.55 no.6
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• pp.940-951
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• 2011

Reaction of 1-methylpyrimidine-(1H,3H,5H)-2,4,6-trione (1-MBA 1) as an unsymmetrical barbituric acid with cyanogen bromide and various aldehydes in the presence of triethylamine and/or pyridine afforded diastereomeric mixtures of new class of heterocyclic stable 5-aryl-1,1'-dimethyl- and 5-aryl-3,1'-dimethyl-1H,1'H-spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine]2,2',4,4',6'(3H,3'H,5H)-pentaones which are dimeric forms of 1-methyl barbiturate at the range of $0^{\circ}C$ to room temperature. In the reaction of some aldehydes with 1-MBA and BrCN were afforded a mixture of diastereomers. Another two aldehydes such as 4-cyano- and 2-hydroxybenzaldehydes gave exclusively two diastereomers in which binded to the salt of triethylammonium hydrobromide by intermolecular H-bond in ratio of 1:1. 4-Hydroxybenzaldehyde and 2-pyridinecarbaldehyde gave exclusively one diastereomer under the same condition. Aldehydes possessing strong electron-donor were produced exclusively two geometric isomers of Knoevenagel adduct (E- and Z-isomers). The structures of compounds were deduced by $^1H$ NMR, $^{13}C$ NMR and FT-IR spectroscopy. Mechanism of the formation is discussed.

• Mycobiology
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• v.37 no.2
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• pp.141-146
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• 2009

Novel copper(II) complexes have been synthesized from the macrocyclic Schiff bases derived from Knoevenagel condensed ${\beta}$-ketoanilides (obtained by the condensation of acetoacetanilide and substituted benzaldehydes), 4-aminoantipyrine and ophenylene diamine. The structural features have been determined from their analytical and spectral data. All the Cu(II) complexes exhibit square planar geometry. Their high molar conductance values support their 1 : 2 electrolytic nature. The magnetic moment data provide evidence for the monomeric nature of the complexes. The X-band ESR spectra of the |$CuL^1$|$(OAc)_2$ in DMSO solution at 300 and 77 K were recorded and their salient features are reported. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by well diffusion method. A comparative study of inhibition values of the Schiff bases and their complexes indicate that complexes exhibit higher antimicrobial activity than the Schiff bases. Copper ions proved to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.629-635
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• 2012

Two novel conjugated copolymers utilizing 4,7-dithien-2-yl-2,1,3-benzothiadiazole (DTBT) coupled with cyano (-CN) substituted vinylene, as the electron deficient moeity, have been synthesized and evaluated in bulk heterojunction solar cell. The electron deficient moeity was coupled with carbazole and fluorene unit by Knoevenagel condition to provide poly(bis-2,7-((Z)-1-cyano-2-(5-(7-(2-thienyl)-2,1,3-benzothiadiazol-4-yl)-2-thienyl)ethenyl)-alt-9-(1-octylnonyl)-9H-carbazol-2-yl-2-butenenitrile) (PCVCNDTBT) and poly(bis-2,7-((Z)-1-cyano-2-(5-(7-(2-thienyl)-2,1,3-benzothiadiazol-4-yl)-2-thienyl)ethenyl)-alt-9,9-dihexyl-9H-fluoren-2-yl) (PFVCNDTBT). The optical band gaps of PCVCNDTBT (1.74 eV) and PFVCNDTBT (1.80 eV) are lower than those of PCDTBT (1.88 eV) and PFVDTBT (2.13 eV), which is advantageous to provide better coverage of the solar spectrum in the longer wavelength region. The high $V_{oc}$ value of the PSC of PCVCNDTBT (~0.91 V) is attributed to its lower HOMO energy level ( 5.6 eV) as compared to PCDTBT ( 5.5 eV). Bulk heterojunction solar cells based on the blends of the polymers with [6,6]phenyl-$C_{61}$-butyric acid methyl ester ($PC_{61}BM$) gave power conversion efficiencies of 0.76% for PCVCNDTBT under AM 1.5, 100 mW/$cm^2$.